Fluid pressure brake equipment



y 1,1951 J. R. AINSWORTH I FLUID PRESSURE BRAKE EQUIPMENT Filed Aug. 19,1949 INVENfOR. John R. Ainsworth ATTOPNE Y Patented May i, 1951 so PATENT o -me $550,900

FEUi D masso an BRAKE EQUIPMENT- '1 dhn ItAinswort h, fie lmont iaassignor to-Jl h'e.

Westinghouse Brake C pant; Wiliiibi dii'ig ,..P'a., a corporation ofPennsylvania Aiiplicatidh iiilgustlti, 1949,-S'erial.No"; 111,159.?

1.- This invention-relates: to afiuidmressure brake-- equipment forrailway .trainsandamore particu; larly to the I straight air-type:

Arstraight. air .brakecequipment as. commonly: known, comprises an;.opera-tors'; brakervalreridee vice for: supplying: and; releasing,,uviaaai straight; airtpipe; fluid. under pressure directly; to .sand:from: a brake. 'cylinderfdev ice. forifapplyingi andreleasingibrakestSuch brakeaequipmentzisreme. ployed on individual; vehiclesloizcnshort'itrains; oh for examplestwolorzthreeavehiclesr- Ittis.impractical forzuseonlonger trainsvahowevee due to;theitiinezrequirediortransmittingtfluidmnderpressure i through .itltie'1straightlair. pipeabetweem thetbrake valvesdevicez mzthe. leading car-f, thetrain::and..,thea vehi'cletatath'e rear 'enell;oiliithei train.z..

Torcontrolhrakesaon' suchciongertrains Yon thea usuallipstraight. air.principle, so '1 called elect'ro pneumatic straight air.brakezequipm'enttthas been employed: which erctromagnetsl=onceachvehiclezncontrolled electricallyifromothe brake waive device on theleading vehicle, are arranged-fitte control substantially:simultane'cusly ithee'supply and release of fluid zunder pressure-ito-'andtfrom the brake cylinderdevice'sio n alllcarspf the train.

For :riew- "light .vv'eig'htI trainsiinowa being". pro posed, it 'isssareqiiisiteithat therbrake eqnip'ment; be as light his weight'aszp'ossi-blei Electroepneu matic .brakaequi'prheritsuoh .asraboveihention'ed" would adequately :brake .=:these :new light weighttrainsbut .irn'avievh ofith'eiire'quirement iior "li'ght--- nessrin:vweightiit esi'rable-tnot to use -electromagnet structures zonrthe-i-vehicles without how ever any. materialxnsacrificeAir: the-1adequacy-50f train; In otheiw words; if the brake svalve' td'evice"is'operatedtto supply-efluid :undenpressureato the; straight air pipe onthe lead vehicle ct the-@traim means on s'aid'sleadivehicle willrespondzitoisuchl supplynto provide a likecsupply; to the second ve-:-

summer (01. 2034s) 2 hicle of the train. and. so on gseriallygthroughoutthe train; Thev means --onthe several vehicles will operate serially inreverse. manner. to dup 1i-..

cate'operation oi the brake valve device to reduce the pressure :offiuid in the straight air pipe... Bye

such operations therewwill beiso little difference between the-time of;'applying1 .the brakes on the. first and:v last: vehiclesof; the 1,train; ,and of- .releasingtsuchi brakes, s as" to-.avoid rough trainhang dling-whileat the same timeprovidingior desired rapidestoppingtoi:the train-.. Whileit is intended: that these :trai-nsnormally operateonly iii-one direction 117*? may. be necessary; in: certain. yardoperations ,that theywbe ioperated; .inthe opposite: direction by alocomotive connectedthereto, andr accordinglto another feature of theinvention the improvedhraliezequipment is operable ii -tithe: samemanner from controll-initiated. from .eitherend rotthe-train." V

Other objects :andadva tages will become .ap-- parent from theiollowing.inore-detailed'descrip tion of: the-inventions V W Ila-theaccompanying; drawing: Fig. ltisian outline. view of theeimproved vbrakeequipment: for a train" ofmvehicles; ,and Figs; 2,; 3-. and: 4-iare1sectionaL I views of diiferent. devices shown in outlinein Fig; ,1.

Description As shown: in .the drawingtthe reference meralll designatesalstraightaimtrainpipeadapt ed to extend through the trainrand to-zbecoupled. bet-ween the different tvehicles; of: the: train .by the X:usual flexible :hosei-Z and-1 hose couplings The brake-equipment rforonlyfithree vehicles is shown in. the drawing; but :it *is desired topoint out that thisais merely;=-illustrative; since a tramemploying, theimproved'equipment may. .be of: any desired: length:

The 'portionvof the straight air :train: pipe 1' l ort each: of thevehieleszapreferably comprises?two sections'.desigriatedcini:the drawingby numerals a:;and.-l-b which-:are separate-d :from-ceaeh rather by a'connecting double check-waiverdevices Theitsbrakeiequipmentiorc'eachz.-vehicle"may fur ther comprise a relay-*valveidevice fiiarranged tooperate t-in :response ."to variations in pressure" eithersectiomsuchtas section lb3 0f the "straight air pipe Jon: theivehicleitoprovideslike variations inzpressuretin'a brake cylinder dviceifi for connected by a pipe It to the devices and 8 and arranged to be suppliedwith fluid under pressure in any suitable manner.

In addition to the above, an operator's brake valve device ll is alsoprovided on the lead vehicle of the train, while the coupling 3 at therear of the train may be closed by the conventional dummy coupling, notshown.

The double check valve device t on each vehicle comprises (Fig. 2) acasing containing a double check valve l2 slidable therein and open atopposite ends to pipes la and lb and at one side to a pipe iii. In theposition in which the double check valve i2 is shown in the drawing itopens pipe la to pipe l3 and closes communi cation between pipe l3 andpipe lb; In an opposite position the double check valve is adapted toclose communication between pipes l3 and la and open pipe l3 to pipe lb.A plunger I4 is slidably mounted in the casing for contact with one sideof the double check valve l2 to lock it against movement. Connected to'the plunger I4 is a flexible diaphragm l5 adapted to be operated byfluid under pressure in a chamber 26 to move plunger i linto suchlocking engagement. Upon venting of fluid under pressure from chamber l6a spring H is adapted to withdraw plunger i from locking engagement withthe double by a stem 26 extending through the bore 2i, the

length of said stem being such as to open either one of said checkvalves When the other is seated. The bore 2i is open through one or moreports 2? to pipe 32. Slidably mounted in the casing and extendingthrough one of the bores 21 is a lock- I ing plunger 2-8'arranged to beoperated into looking engagement with stem 26 by pressure'of fluid in achamber 29 acting on a diaphragm 30. When chamber 29 is void of fluidunder pressure a spring 3i is adapted to remove the stem 28 from lookingengagement with stem 26. Chamber 29 is open to pipe 32.

The straight air control transmitting device 8 may, for the purpose ofillustration, comprise a casing containing a flexible diaphragm 33 atone side of which is a control chamber 34 open to pipe l3 while at theopposite side is a chamber 35. Also at the opposite side of diaphragm 33are two spaced apart poppet valves 36 and 3?, constituting fluidpressure release and fluid pressure supply valves, arranged in coaxialrelation to said diaphragm for control thereby.

= The valve 31 is arranged to seat in the direction of diaphragm 33against an annular seat rib 38 for closing communication between a fluidpressure supply chamber 39 open to the seating side of said valve and topipe Ill, and a chamber 33 open to pipe 32. The valve 31 isslidablymounted in a bore in the casing and at the side opposite theseat rib 38 is connected by a stem .6 to a piston 4| slidably mounted ina bore in the casing which latter bore, and thereby piston @l, 'is ofsubstantially the same diameter as seat. 38. At the opposite side ofpiston ll is a chamber 42 open to chamber 40 through a 4 bore 43 andcontaining a spring 44 acting on piston Al for urging valve 31 intoengagement with its seat 38. Since the piston 4| is of substantially thesame diameter as the seat 33 it will be seen that the opposing forcesincident to pressure of fluid acting on opposite sides of the valve 31and piston 4| are substantially the same so that spring M need onlyexert relatively light pressure on said piston to seat said valve and acorrespondingly light pressure is required on said valve to unseat itagainst said spring.

The valve 36 is arranged to seat in the direction of valve 3'! againstan annular seat rib 45 for closing communication between chamber 46 andan atmospheric passage 46. The valve 35 is slidably mounted in a bore inthe casing and connected bya stem 41 to a piston 48 also slidablymounted in the casing. Chamber 4D is open through a bore 49 to a chamber53 at the opposite side of piston 48 and the diameter of said piston issubstantially the same as the inside diameter of the valve seat 45 toprovide a valve structure which is substantially balanced with respectto forces incident to pressures of fluid in chambers 56, 53 and actingon adjacent faces of said piston and valve 35. A light bias spring inchamber 53 acts on valve 36 for urging it into contact with seat 45.Chamber 5G is open through a small port 5| to chamber 35 at the ad acentside of diaphragm 3|.

A stem 52 slidably mounted in the casing in two spaced bearing 53 andextending through chambers GE] and 53 and with annular clearance throughbore 39 is connected at one end to the diaphragm 33 for movementtherewith. The opposite end of stem 52 is arranged for engagement withthe seating face of valve 31 within the seat rib 33. A shoulder i isprovided on stem 52 within chamber 453 to engage and unseat the valve 33by movement of stem 52 in the direction of the left hand. A bias spring55 in chamber 34 acts on diaphragm 33 to hold it against stem 52.

Operation of the straight air control transmitting device 8 is asfollows:

Letit be assumed that initially both valves 36 and 3's are seated andthat diaphragm 33 is in a neutralposition in which position these partsare shown in the drawing. Let it further be assumed that the reservoir 9is charged with fluid under pressure and hence the supply valve chamber39 correspondingly charged.

Now let it be assumed that fluid is supplied to chamber 34 at a pressuresuflicient to deflect diaphragm 33. against pressure in chamber 35. Thediaphragm 33 will then deflect in the direction of the right hand movingthe stem 52 through and hence relative to the seated release valve 39into contact with the supply valve 3'1 and when sufficient furtherincrease in pressure of fluid is then obtained in chamber 34 to overcomespring 65, said diaphragm through the medium of stem 52 will open saidsupply valve. Fluid under pressure from the reservoir 9- and chamber 39will then flow past the open supply valve 31 to'chamber 48 and thence topipe 32. At the same time as fluid is thus supplied to pipe l3, fluidwill also flow from chamber 40 through bore d9 in the release valve 36to chamber 50 to maintain a balance of fluid pressures in said chambersacting opposingly on said valve and piston 48 so that spring 56 may holdsaid valve seated. Fluid under pressure from chamber 50 .will also flowthrough port 5| to chamber 35 whereby the pressure of fluid in thelatfluid underpreSsureWiIl be're'le'ased fronrpip'e' assessetei' clim erwill increasefsubstanti'ally'witli the increase in pressure in pipe I3.

I, New assumethat the increase in pressureof fluid" chamber 3 is limitedto some chosen" degree. When the pressureof'fluid in pipe 32aiidehamberts' is built up to substantially the dg' setting-incha'mbertdthe" spring lifl will" move the supply valve 3? back intocontact with" its" seat" 38' and at the sametimereturn the diap ragm"33" to its" neutral position, trierei'oy'- limiting'the "ess'ure offluid 'obtained'in pipe 32" tdslib'stantially the'sain'e degree asprovided in dhamb'er '34;

Itwillbe' apparent from'theabov'e description" v 32, chambers iii andfiliandthrough'the medium of port El from chambered. When the'pr'essure'of' fluid in chamber then becomes" re ,duced to substantially thesame degree'as that' still effective in chamber 34 spring will do fleetdiaphragm 33 toward the right handut'o permitcids'ing' ortherelease'valve 35 hy' sprin'g' ssfto thereby limit the reduction inpressure pipe" '32" to substantially thesame degree asth'e reduction" inchamber 341 It Will now'be ap= parent that for any reduction inpressure-flof fluid in chamber 34 a corresponding reduction pressure offluid will occur in' piped? if the pressure of fluid in chamber 34 isreduced to" atmospheric pressurethe'pressure in chamber 35 andhenceinpipe'32will reduce to substam tiall'y the same 'pressure beforethe voice or spring 5501} diaphragm 33 and of spring' ii6' o'ii' va1ve36will predominate; whereupon the vaive 36'Wi11 be closed; For allpractical purposes the pressureo'f fluid in pipe 32 will be "atmosphericpressure" upon such closing of valve 36.

It will nowbe seen that the valve"device twill respdndto anypres'sur'eof fluid providedinpipe l3, and any increase or decrease in such pres=sure to provide a substantially like ressure in pipe'32- The relay valvedevice 5 may, for illustration; be like the straight air control device'firforvary ing pressure of fluidin the brake cylinder device '6- inaoc'or'da'nce with variations in control pressure in pipe lb.

The-operators control valve device M be of any suitable structure, asfor example like that disclosed in U. S. Patent 2,042,112, issued on May29, i936 to E. K. Lynn et a1. and will therefore be only brieflydescribed particularly since devices of this general type are so wellknown.

The brake valve device l'l comprises an ops control handle 51 and valvemeans (not adjustable by said handle" upon movenrent-out of a normalposition, in which it is shown in the drawing, toward the right hand, oruponreturriniovement toward the leftliand tdprbifid in'the connected''-pipe la fl-hid ate pressure-proportional tothe disliance 'said"handle" isoutpr the normal position: ln 'the normal positionof handle-51 the connected pipe la maybe opento atmosphere.

Operation of equipment the assumed that several vehi'cl'es 'prov idedwith the improved brake equipment are connected in a" train, as showninfthe drawing,x

that theire'servoirs 9 are charged with fluidunder: pressure and thatthe handle" 51 ofv the brake: valve-device ll on the'leading vehicle isin its. normal position opening the connected pipe la.

to' atinosphere'i With pipe la onlthe' leading vehiele opei itoatmosphere, pipe lb on said vehicle" and pi es la and lb on all of theother vehicles: will likewise beat atmospheric pressure, the: reiayvalvedevices 8 on the several vehicles-will be intheir brake releaseposition, in which the parts ar'eshown' inFig. llof the drawing; and

the relay valve devices 5 will likewise be positioned with the brakecylinder devices 6 vented:

to atmosphere, as will become apparent from the description to follow:

With thebrakes on the train thus released; if;

l d. The fluid under pressure thus suppliedtov pipe la on theleadingvehicle will flow into cham ber l8 ofthe respective double checkvalve .deviee I- wherein such pressure acting on check valve 25 "will"seat same and open the checktva-lve 2 5, in case these'valves' arenotalreadyso' positioned. At the same time; fluid from pipe lazconnectedto the brake valve device will flow to. and. act on the lefthand endofthe'double checkrvalve l2 in the device l onthe leading vehicle andmove said valve to its right hand position, if not already sopositioned, and then-flow past the left. hand end of said valve andthrough pipe l3 to' diaphragm chamber 34 in the straight air con.-troltransmitting device 8* on the le'adingve'hicle and actuate saidtransmitting-deviceto supplypastthe open valve 25 in the double check:valve device I" fluid at a corresponding pressure to pipe lb 011 theleading vehicle.

Fluid under pressure thus supplied to pipe lb on the leading vehiclewill flow to pipe la on the second vehicle in the train and, as on theleading vehicle; position the double check valve devices 4 and l andoperate the transmitting device 8 thereonto supply to pipe lb on saidsecondvehicle fluid at substantially the same pressure as provided inpipe la on the leading vehicle, and this action will be thus transmittedserially from one vehicle to another to the rear of the train at whichposition the pressure of fluid obtained in pipe lb will also besubstantially equal to that provided in pipe ia on the leading vehicle.

It is to be noted that the brake valve device ll suppliesfluidunder'pressureto operate only the transmitting device 8 on theleading vehicleof the train and said transmitting device operates tosupply froma local source fluid to operate -only the relay valve device5 on that vehicleand the. transmitting valve device 8 on the next-cartothe rear, and so on through the train. With the V transmitting deviceslivery sensitive to pressure changes inchamber 34 to reproduce only in theconnected sections l b and. l-w o'f'the straight air pipe on therespective vehicle and the connected vehicle to the rear a rapidincrease in pressure in the train straight air pipe l may be obtained,and in response to such increase the relay valve devices will seriallyoperate to supply fluid at a corresponding pressure to the brakecylinder devices 6 for applying the train brakes.

If only a partial degree of brake application is effected, the degreemay be increased by moving the brake valve handle 51 further toward theright hand for effecting an increase in pressure of fluid in theconnected pipe la. In response to such increase the transmitting device8 on the leading vehicle and then on the next vehicle, and thus seriallythrough the train, will operate to effect a corresponding increase inpressure in the connected straight air pipes sections lb, la to the rearand the relay valves 5 will operate serially to provide a correspondingincrease in pressure in the brake cylinder device 6 and thereby acorresponding increase in the degree of brake application on the train,in the same manner as above described.

It will thus be seen that a brake application may be limited to anydesired degree and increased in degree if desired, in any desired steps.

When an application of brakes is effected on a train, as just described,fluid under pressure supplied to pipe 32 On each vehicle will flow todiaphragm chambers l6 and 28 in the double check valve devices 4 and Iand operate the diaphragms l5, 3%] to move the locking stems Hi, 28 intolocking engagement with the double check valve l2 and stem 26 of thedouble checking valve device 1 for holding the parts of said devices inthe position to which they were moved, for reasonswhich will bepresently brought out.

In order to release an application of brakes on the train, the brakevalve handle 5? will be moved back toward its normal position. If lessthan a full release of brakes is desired the handle will be stoppedshort of its normal position according to the degree of brakeapplication which it is desired to retain, while in case a full releaseis desired the handle will be moved to said position.

Let it be assumed that the hande 5? is stopped short of normal positionin which case the pressure of fluid in the connected pipe la Will bemerely reduced to a corresponding degree, and a like reduction inpressure will occur on the left hand end of the double check valve l2and in chamber l8 of the double check valve device l on the leadingvehicle, but due to the locking action of stems l4 and 28 said checkvalve and the parts of the check valve device I will remain in theposition to which they were moved in elf-ecting an application of brakesagainst the opposing higher pressure of fluid in the connected pipe lb.Thus as the pressure of fluid in pipe la on the leading vehicle isreduced, a like reduction in pressure will occur in diaphragm chamber 34of the transmitting device 8 on said vehicle and said transmittingdevice will operate to efiect a corresponding reduction in pressure inthe connected pipe lb. Such reduction in pressure in pipe lb on theleading vehicle will be transmitted to the transmitting device 8 on thesecond vehicle of the train which will operate to effect a likereduction in pressure in pipe lb on said second vehicle, and so onserially through the train, the pressure of fluid in the straight airpipe being thus reduced to substantially the same degree as in pipe laon the leading vehicle. In response to such reduction in pressure inpipe lb on the several vehicles the relay valve devices 5 will seriallyoperate to efiect a like reduction in pressure in the brake cylinderdevices 6 and hence a corresponding reduction in the degree of brakeapplication on the vehicles of the train.

If the brake valve handle 51 is moved further toward its normal positionthe brakes on the vehicles of the train will be serially releasedaccordingly while upon movement to said normal position for completelyventing the connected pipe la, the transmitting devices 8 will operateas above described to reduce the pressure of fluid in the connectedpipes lb to substantially the same pressure whereby the relay valvedevices 5 will operate accordingly to efiect a substantially fullrelease of fluid under pressure from the brake cylinder devices 6 andthereby a complete release of brakes. The locking pins l4 and 28 willremain effective until the pressure in the connected pipes 32 is reducedto the degree to provide a full release of brakes.

It will now be seen that an application of brakes on the train may bereleased in steps or a continuous complete release may be efiected asdesired.

It will also be apparent from the above description that by appropriatemanipulation of the brake valve handle 51 the brakes on the train may beapplied to any desired degree, partially released and then reapplied asdesired for adequate control of the train under different circumstances.

It will be noted that the brake valve device ll controls the fluidpressure only in chamber 34 of the transmitting device 8 on the leadingvehicle and that said transmitting device on the leadin vehicle, and thetransmitting device on each of the following vehicles, controls thefluid pressure for controlling operation of the relay valve devices 5 onthe respective vehicles and also of the transmitting device on the nextvehicle to the rear, the double check valve devices 4 and l closingcommunication between the straight air pipe sections la and lb on eachvehicle to provide such control.

If the train brakes were to be controlled only from the brake valvedevice 51 at the one end of the train, the double check valves 4 and 1could be dispensed with and the pipes la and lb on each vehicleconnected directly to chambers 34 and 40 of the respective transmittingdevice. However the double check valves 4 and l are essential to providefor control of the train brakes from the end of the train opposite thebrake valve device I l as during switching or yard operations by thebrake valve device (not shown) on a yard locomotive.

If a yard locomotive is connected to the end of the train opposite thebrake valve device II and the brake valve device on said locomotiveconnected to the straight air pipe l, operation of the latter brakevalve device to supply fluid under pressure to the connected portion lbof the straight air pipe will shift the double check valves 1 and 4thereon to permit such fluid to become eiiective in chamber 34 of therespective transmitting device 8 to operate same to supply fluid to theconnected pipe la and to pipe lb on the next vehicle, whereby the brakeequipments on the vehicles of the train will operate serially to efiecta serial application of brakes on said vehicles in the same manner aswhen controlled by the brake valve device I I. As will be apparent, thebrakes on the train may be graduated or in steps and released asdesired, in the same manner ,.e s ulieaso i rcl e immmtheb ake va edwnenn brake an he ra n arewn r l prom theendppposite the brake valvedevice H, do eratiq of the transmitting device 3 on the velncle carryingsaid brake valve device is not essenjfial since it willmerely supplyfluid to pipe is ,Cpnnected to said brake valve device, the br kesonsaid vehicle being applied by fluid under pree-= the Vehicle and foropening said other chamber sirable since it would act to dissipate thesupply of fluid under pressure from reservoir 9 for applying the brakeson the vehicle, but this may be @Noicled by the provision of a cut-outcock 55 in -pipe,- la,at the brake valve device which will be It willnow be seen that I have provided a purely straight air brake equipmentparticularly adapted for use on vehicles operative in trains fortransmitting a pressure change serially from one vehicle to anotherthrough a train at such a rate as to provide desired control of brakingof said train. Each vehicle is provided with a source of fluid underpressure and a valve device responsive to a pressure change in thestraight air pipe section extending toward the leading end of thevehicle to provide from said source a like change in pressure in thestraight air pipe section extending toward the opposite end of thevehicle whereby the speed of serial operation of the equipments issubstantially independent of the transmission of any material quantityof fluid under pressure on any one vehicle which would tend to slow upsuch operation.

Having now described the invention, what I claim as new and desire tosecure by Letters Patent, is:

1. A straight air brake equipment for a train of connected vehiclescomprising in combination, a straight air pipe adapted to extend throughthe train, a straight air transmitting device for each vehiclecomprising means responsive to variations in pressure in one chamber toefiect like variations in pressure in a. second chamber, means on eachvehicle opening said chambers to portions of said straight air pipe onthe vehicle which are spaced apart lengthwise of the vehicle, and anoperators straight air brake valve device connected to one end of saidstraight air pipe for initiating variations in pressure therein.

2'. A straight air brake equipment. for a train of connected vehiclescomprising in combination, a straight air pipe adapted to extend throughthe train, a source of fluid under pressure for each vehicle, meansadapted to be carried on each vehicle responsive to an increase inpressure in one chamber to open said source of fluid under pressure toanother chamber and respon-.

sive to equalization of pressures in said one chamber to close saidsecond chamber from said source and responsive to a reduction inpressure in said one chamber to open said other chamber to atmosphere,means adapted to be carried on each vehicle for opening said one chamberto said straight air pipe adjacent the leading end of I end ofthevehicle, and an operators straight air brake valve device connected toone end of said straight air pipe'for initiating variations in pressuretherein.

,3. A straight air brake equipment for a train of connected vehiclescomprising in combination, a straight air pipe adapted ,to extendthrough the train, and comprising for each vehicle a first portionadapted to extend to one end of thevehicle and a second portion adaptedto extend to the opposite end of the vehicle, a straight airtransmitting device for each vehicle responsive to variations inpressure in one of said portions to effect like variations in pressurein the other portion, and an operators straight air brake valve deviceadapted to be carried by the vehicle at one end of the train foreffecting variations in pressure in the said one portion of the straightair pipe thereon.

i. A straight air brake equipment for a train of connected vehiclescomprising in combination. a straight air pipe adapted to extend throughthe train, and comprising for each vehicle a first portion adapted toextend to one end of the vehicle and a second portion adapted to extendto the opposite end of the vehicle, a pressure transmitting device foreach vehicle responsive to variations in pressure in one chamber toeffect like variations in pressure in another chamber, and valve meansfor each vehicle responsive to variations in pressure of fluid initiatedin either one of said portions to open said one chamber to the lastnamed portion and said other chamber to the other said portion on thevehicle.

5. A straight air brake equipment for a vehicle of a train comprising incombination, a straight air brake control pipe adapted to extend thelength of said vehicle, a pressure transmitting device responsive tovariations in pressure in one chamber to effect like variations inpressure in another chamber, and valve means dividing said pipe into twoportions and responsive to supply of fluid under pressure to either oneof said portions with the other portion vented to open said one chamberto the last named portion and the other chamber to the other portion.

6. A straight air brake equipment for a vehicle of a train comprising incombination, a straight air brake control pipe adapted to extend thelength of said vehicle, a pressure transmitting device responsive tovariations in pressure in one chamber to effect like variations inpressure in another chamber, valve means subject opposingly to pressuresof fluid in said pipe at opposite ends of the vehicle and operative uponsupply of fluid under pressure to said pipe at either end of the vehiclewith said pipe at the opposite end at atmospheric pressure to a positionto open said one chamber to the end of said pipe supplied with fluidunder pressure and the other chamber to the other end of said pipe, andmeans responsive to atmospheric pressurein said other chamber to rendersaid valve means movable and to a higher pressure in said other chamberto hold said valve means against movement.

7. A straight air brake equipment for a vehicle of a train comprising incombination, a straight air brake control pipe adapted to extend thelength of said vehicle, a pressure transmitting device responsive tovariations in pressure in one chamber to effect like-variations inpressure in another chamber, double check valve means dividing said pipeinto two portions one for extending to one endof the vehicle and theother to the oppositeend and operative in response to supply of fluidunder pressure to either portion, with the other portion vented, to aposition for opening said one chamber to the portion thus supplied withfluid under pressure and for closing said one chamber off from the otherportion,

another double check valve means operative in response to supply offluid under pressure to valve means for movement upon release of fluidunder pressure from said other chamber.

8. A straight air brake equipment for a vehip 12 c c ole of a traincomprising in combination, two straight air brake pipe sections oneadapted to extend to one end of the vehicle and the other to theopposite end for connection with a like section on a connected vehicle,a source of fluid under pressure, valve means arranged to respond tovariations in pressure in said one section to effect variations inpressure in the'other section, and brake control means responsive topressure changes'in one of said sections to efiect braking of thevehicle in proportion.

JOHN R. AINSWORTH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS 7 Number Name c Date 20 1,765,634 Stewart June 29,1930 2,068,319 Fitch Jan. 19, 1937

